The disclosure relates to a linear actuator which serves to move a load. One preferred field of use is movement systems such as driving simulators and flight simulators, in which a cab is mounted on a platform which can be moved in six degrees of freedom by a total of six identical linear actuators. Linear actuators are known which have an actuator housing with a tube, with a housing bottom at the one end of the tube and with a housing head at the other end of the tube, a piston which is guided longitudinally in the actuator housing, and an actuator rod which is assembled with the piston and protrudes out of the actuator housing in a manner which is guided on the housing head.
Linear actuators of this type are often electromechanical linear actuators, there being a threaded spindle which can be driven rotatably by an electric motor, is mounted rotatably in the housing bottom of the actuator housing and extends in the interior of the actuator housing from the housing bottom in the direction of the housing head, the piston comprising a spindle nut which is in engagement with the threaded spindle, and the actuator rod being hollow and the threaded spindle dipping into the hollow actuator rod.
It is also known to equip a linear actuator of this type with means for compensating for the static load, up to 75% of the static load being supported, for example, by way of said means. The remaining proportion of the load is absorbed by the threaded spindle. If a plurality of linear actuators are provided to carry the load, each linear actuator of course accepts only a certain proportion of the load. If desired, up to 100% of the static load can also be compensated for.
In an emergency or in the case of incorrect control, it can occur that, depending on the movement direction and structural design, the piston impacts against the housing bottom or against the housing head or a flange which is fastened to the outside of the actuator rod impacts against the housing head. Here, damage of structurally essential parts can occur which is such that said parts have to be replaced. On account of the damage, the actuator can also be blocked, with the result that emergency operation is no longer possible. There is also the risk that people are injured who are situated in the cab of the simulator and who are subjected to large negative accelerations in the case of an impact of the piston or the actuator rod.